Many Worry About Forms Getting Lost

There is one statistic the U.S. Census Bureau does not keep or even try to tabulate, and that is how many completed questionnaires get lost rather than counted.

The government is spending $73 million to promote the idea that all responses are, by law, kept confidential. Left unsaid is that the law is only as good as mail service - and mail does get lost.

''I would think that (the number of lost questionnaires) is very small,'' said Census spokesman Ray Bancroft in Washington. ''I think the post office has a very good record on delivering the mail, particularly first-class mail.''

Judging by its own records, the postal service's delivery rate is a good one. During the past fiscal year it handled 161 billion pieces of mail; only 544,941 were reported lost.

That's a mere fraction of one percent, and if used to project how many of this year's 106 million Census forms will not find their way back to district offices, the answer is all but three or four.

However, Jane Schoefer, a Maryland postal inspector, warned that the percentage of mail lost is probably greater. The fraction reflects only the mail that people were expecting and did not receive.

There are people who contend that if three or 3,000 Census forms are lost this year, the principle is the same. The government's guarantee of confidentiality is to be questioned.

The Voluntary Census Committee, a 30-member group based in California, contends that anything short of a voluntary Census is an invasion of privacy - even if the information collected is kept confidential.

In 1970, director Lawrence Samuels said he and his committee persuaded several hundred citizens with similar views about the Census to burn their questionnaires and risk a $100 fine.

No one was fined, Samuels said, even though several newspapers reported on the activities. No one did anything,'' he said, ''and I had my picture in the Los Angeles Times. I think it (the threat of a fine) is more of a bluff.''

Danny Twedt heads another anti-Census group, the 2,000-member Society for Libertarian Life in California. He too is troubled by the prospect of the government losing Census responses but not surprised.

''Of course, I don't think the government is very good at guaranteeing the confidentiality of anything,'' Twedt said.

The penalty for tampering with Census forms is a $5,000 fine and up to five years in prison. Census officials said they knew of no cases where anyone was convicted of circulating information given by citizens.

However, a 1980 Census worker was imprisoned for leaking a mailing list, said spokeswoman Kelly Garcia in Maryland.

''Confidentiality is something we do stand by,'' Garcia said. ''Even the president of the United States can't get this information.''